Wealth Begets Health, Even in Lung Disease

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This study was published as an abstract and presented at a conference. These data and conclusions should be considered to be preliminary until published in a peer-reviewed journal.

Higher socioeconomic status in patients with lung cancer and chronic obstructive pulmonary disease (COPD) is associated with more favorable prognosis and longer survival.

Note that median survival time was higher in those of higher socioeconomic status with COPD and lung cancer compared with those of lower socioeconomic status.

ATLANTA -- Higher socioeconomic status in patients with lung cancer and chronic obstructive pulmonary disease (COPD) is associated with more favorable prognosis and longer survival, a researcher said here.

Diagnoses of non-small cell lung cancer (NSCLC) were significantly more likely to occur at disease stage I in individuals of higher socioeconomic status who also had COPD, and such patients were significantly more likely to receive surgical or first-line chemotherapy, relative to COPD patients of lower status, said Janaki Deepak, MD, of the University of Maryland School of Medicine in Baltimore.

Median survival time in higher-status NSCLC/COPD patients also had a mean survival time of 247 days, compared with 201 days for lower-status patients (P<0.05), she told attendees at the American College of Chest Physicians annual meeting.

The study was based on data from the federal government's Surveillance, Epidemiology, and End Results (SEER) registry and linked Medicare records.

Similar findings were seen among COPD patients diagnosed with small-cell lung cancer, Deepak said.

She said the socioeconomic study looked at patients with both COPD and lung cancer because smoking is more common in lower-status individuals and because it's a "common pathway" to both diseases.

She also pointed out that previous studies had documented a decreased likelihood of survival and aggressive treatment associated with lower socioeconomic status in lung cancer patients.

But whether that association also applied in patients with both conditions were unclear, she said.

In the current analysis, Deepak and colleagues sought to confirm that both COPD and lower socioeconomic status would correlate with later stages of lung cancer diagnosis, lower likelihood of curative treatment, and poorer survival.

Patients from the federal databases with lung cancer diagnosed from 2001 to 2005 were included in the study, stratified by diagnosis of small versus non-small cell lung cancer.

Those without continuous Medicare coverage starting from one year before diagnosis and ending at last follow-up were excluded, as were patients with missing data concerning date of diagnosis and vital status.

The final sample included 34,237 NSCLC cases and 5,232 small cell lung cancer patients. Both groups were divided about equally between high and low socioeconomic status individuals.

Socioeconomic status was determined from data on Medicaid enrollment records and race, and on census tract or zip code averages for income, education, and language ability for the patient's primary residence.

Status index values were calculated and patients in the middle tertile was excluded, leaving the upper tertile as "high" status and the lower tertile as "low" status.

Of the 34,237 NSCLC patients, 17,347 were of high status, and 4,505 of them had COPD (26%) according to their Medicare claims data. Another 16,890 were of low status, of whom 6,200 had COPD (36.7%) -- a disproportionately high share, compared with the high-status group.

In the 5,232 with small cell disease, 2,386 were of high-status, of whom 705 had COPD (29.5%). The remaining 2,846 were of low-status, and 1,169 of them had COPD (41.1%).

The comparisons presented by Deepak addressed only the patients with both lung cancer and COPD.

She reported that patients with both conditions who were of lower socioeconomic status were significantly more likely to have more comorbidities (P<0.000001) than the high-status group.

About 29% of cases involving NSCLC in high-status individuals were diagnosed at stage I, versus 26% of cases in low-status patients; there was a similar difference, but in the other direction, for NSCLC diagnosed at stages IIIb and IV (both P<0.05).

Radiation treatment was given equally to NSCLC patients of low and high status, but surgery after diagnosis was performed in about 25% of high-status patients versus 18% of low-status cases (P<0.05).

First-line chemotherapy was given in about 32% and 25% of high- and low-status cases, respectively (P<0.05).

Similar differences, also with P<0.05, were seen between high- and low-status cases involving small cell lung cancer, although the absolute numbers varied. Surgery was rarely performed in these cases, whereas about half of patients received first-line chemotherapy -- with both moderately more common in high-status patients.

Median survival time in small-cell lung cancer patients with COPD was 162 days for high status and 141 for low status (P<0.05).

Deepak speculated that high-status patients with COPD were more likely to have primary care and/or pulmonologist follow-up, leading to the earlier cancer diagnoses. Such improved care could also translate to better treatment of complications arising from cancer and its therapy, she said.

Limitations to the study included its reliance on administrative claims data, use of geographic averages to estimate patients' income and other socioeconomic characteristics, and lack of adjustment for patient characteristics and treatment in the median survival results.

The study had no external funding.

Study authors declared they had no relevant financial interests.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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